JPH0435751A - Superfine powder classifier - Google Patents

Abstract

PURPOSE:To continuously carry out the classification of superfine powder with high preciseness and to facilitate the maintenance by opening a supply port of material to be classified and providing the flow passage having annular cross-section or plural pipe ways having same cross-section disposed on the same circumference symmetrical to the axis so as to be freely rotatable. CONSTITUTION:The material S to be classified in the mixed state of coarse powder and fine powder is sent in the classifier from the supply port 2, and receives the centrifugal force in the pipe ways 3 rotated in high speed, and the classifying action works by the difference of centrifugal force due to the difference of particle size. Moreover, the pipe ways 3 are forwardly spread in the shape of unfolded fan so that the material receives stronger centrifugal force and advancing action in the pipe ways and smoothly reaches the terminal end. Projecting separation plates 5 are protruded to the flow passage so that the coarse powder and fine powder which are already separated respectively to the outside and to the inside of the pipe ways and flow forward, are clearly separated from their advancing ways, and only coarse powder G is separated to the outside through coarse powder discharge ports 4. The remained fine powder separated by the separation plates 5 is introduced to pipe ways 6 of fine powder, and advances to be recovered from a discharge port 7 of fine powder as fine powder F. By this method, only the fine powder of uniform particle size in high preciseness is always separated and recovered.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to an ultrafine powder classifier that is essential for handling the latest fine powder materials including new ceramics.

Conventional technology: Separating a mixed powder mixture of coarse particles and fine particles by particle size and extracting the desired particles (only ¥) with high precision is a new ceramics technology. This technology is required in a wide range of fields, including manufacturing.

For this reason, much research and development has been carried out to treat solid-liquid slurry containing powder and granular materials and to separate and recover only the solid components by processing dust-containing airflow.

A method of classifying fine powder by rapidly changing the direction of an air flow containing powder and granules and utilizing inertial force is called inertial classification, and FIG. 6 of JP-A-55-167072 will be described as an example thereof.

In the figure, air inside the sealed container 10 is suctioned to create a negative pressure, and a pipe line 11 through which a solid-gas mixed air flow is passed.
When the nozzle 12 is formed by opening the nozzle 12, only the fine powder Fa is sucked through the nozzle and guided out of the pipe, and the coarse particles Ga<3 are allowed to pass through the pipe as they are due to inertia and are handled to achieve coarse classification. It is.

The free-vortex type, which swirls airflow to move centrifugal force to separate and collect only powder, is widely used as a cyclone in dust collectors, and many proposals have been made to improve the separation effect (for example, Japanese Patent Application Laid-Open No. 59-49817 Figure 7).

On the other hand, there is also a batch centrifuge that processes solid-liquid mixed slurry and collects only fine powder with a desired rI of less than 1 yen in a field of centrifugal force (for example, Japanese Patent Laid-Open No. 63-22475
Publication No. 2, Figure 8).

In the figure, a cylindrical rotating bowl 15 held on a rotating shaft 14 within a fixed casing 13 is rotated at high speed. The slurry of material is supplied from the supply port 16 at the lower part of the inner side of the rotating bowl, and is classified by the centrifugal force caused by the rotation, and is divided into only fine powder and liquid from the take-out port 1 at the upper part of the rotating bowl.
7 and collected. The gist of this invention is that since the supplied slurry reaches the outlet too quickly and the classification effect is extremely insufficient, a submerged weir 18 is also provided to cross the flow direction of the slurry.

1. Invention or problem to be solved 1. The inertial force method, which is the prior art listed first, has a weak separation force and only acts instantaneously at the opening (nozzle) inside the seal. Even with the suction power, it must be said that the efficiency is at an extremely low level.

The method that uses centrifugal force due to swirling flow is originally a solid (dust)
The mission is to separate the powder from the gas, and in order to roughly separate and recover the powder and granules by particle size, a powerful airflow velocity and a vast separation chamber are required, so the equipment area and space are limited. Considering the cost, it is considered difficult to adopt this method.

Wet classification of slurry utilizes the difference in centrifugal force in a rotating bowl, and is a typical method for centrifugal separators. Regarding this method, the sedimentation speed of particles larger than a predetermined particle size is increased by centrifugal force to deposit them in the sediment layer Gb in a short time, and the fine particle layer slurry Fb is classified and collected, or the fine particles do not go to the sediment layer and are The amount remaining in the layer slurry can be determined theoretically using Stokes' resistance equation, but this equation can only be applied to slurries with extremely small concentrations, so it is non-industrial, and at an actual production level, rotation Since the slurry in the hole stays as a put stock during operation, even if it is supplied later, it is thought that there is very little room for classification due to short-circuiting due to upward slipping on the equilibrium liquid level of the slurry. In order to prevent such short circuits, the slurry 1B is installed to extend the residence time of the supplied slurry in the rotating bowl, keeping it in the field of centrifugal force, and improving the classification accuracy. As long as the operation is continued, the thickness of the precipitate layer adhering to the inner wall of the rotating bowl will only increase, so it is safe to say that the strength of the centrifugal force will decrease and the accuracy of classification will gradually decrease. Isn't it? Other methods that utilize the centrifugal force field in a rotating body always have the problem of continuing classification or inducing deterioration in accuracy.

In order to solve the above problems, the present invention uses a dry method (airflow),
The purpose of the present invention is to provide an ultrafine powder classifier that can always maintain highly accurate ultrafine powder classification regardless of wet type (slurry), has a simple configuration, and is easy to maintain.

Means for Solving the Problems 1 The ultrafine powder separation @ machine according to the present invention has a feed port for the material to be classified that is opened on the axis of rotation, spreads out at an angle symmetrically from the axis, and has an annular cross section. Alternatively, a plurality of conduits with the same cross-sectional shape arranged evenly on the same circumference symmetrical to the axis are rotatably provided, and the conduit can be installed at the end of the distal expansion or in addition to this, in the middle of the conduit. A tubular coarse powder discharge port attached to each pipe having a ring shape or the same cross-sectional shape with a separating plate protruding toward the upstream side of the pipe is opened, and a fine powder pipe that short-circuits both discharge ports is arranged on the axis. The above problem was solved by opening the fine powder discharge port.

Another method is to open the supply port for the material to be classified on the axis of rotation, expand at an angle symmetrically with respect to the axis, and have a circular cross section or a tube of the same shape symmetrical with respect to the axis. A plurality of conduits are rotatably arranged in such a manner that the conduits are equally distributed on the same circumference, and each of the conduits is partitioned by at least one separation plate that protrudes toward the upstream side of the conduit at the end of the divergent end. It has been shown that the same purpose can be achieved by opening respective discharge ports for the coarse powder and fine powder, and as another means, the supply port for the material to be classified is opened on the axis of rotation, and the discharge port for the material to be classified is opened on the axis of rotation. Spread out symmetrically at an angle,
An annular pipe or a plurality of pipes with the same cross-sectional shape arranged evenly on the same circumference that is symmetrical with respect to the axis are rotatably provided, and a pipe is installed upstream of the pipe in the middle of expansion. By opening at least one or more sets of annular or tubular coarse powder discharge ports each having a sideward protruding separation plate and having the same cross-sectional shape and a fine powder discharge port having the same shape at the end of the expanding end. was also shown to achieve the objective.

[Operation/Example] Figure 1A1 is a vertical sectional view of an embodiment of the present invention, and Figure 2A2 and C show three aspects of the AA cross section in Figure 1. The present invention will be explained in detail based on this example.

The supply port 2 for the material S to be classified is opened at one end of the rotational axis C of the ultrafine powder @ machine 1, and the conduit 3, which always expands symmetrically at an angle from the axis C, has a cross section cut at right angles to the axis. Or, as shown in Figure 2 A, the pipes form an annular shape along the entire length, or pipes with the same cross-sectional shape symmetrically with respect to the axis are machined evenly on the same circumference as shown in Figure 2 and C. attached and placed. In other words, in Figure A, the hollow cone consists of two large and small diameter funnels stacked one on top of the other at a regular interval, while Mello has two inclined belt-like bodies with only a portion cut out, symmetrical to the axis, at the base. It is a connected form.

This pipe line 3 widens away from the axis on the downstream side of the flow of the material to be classified, opens an annular coarse powder discharge port 4 at the farthest end, and from this open end upstream of the pipe line. A separating plate 5 is provided to protrude toward the side (inlet side). Therefore, the material S to be classified, which is fed into the machine from the supply port 2 in a mixed state of coarse and fine powder, is subjected to centrifugal force in the rapidly rotating pipe 3, and the coarse powder is pushed toward the outer circumference of the pipe. When crushed, the difference in centrifugal force due to the difference in particle size causes a classification effect.

Furthermore, as the pipe 3 moves forward, it becomes wider and receives a stronger centrifugal force, so that the material is classified and moved further in the pipe, smoothly reaching the end. The protruding separation plate 5 here protrudes toward the flow path and clearly divides the course of the coarse powder and fine powder that have already separated into the outer circumferential side and the inner circumferential side of the conduit and progressed, Only the coarse powder G is separated to the outside through a coarse powder discharge port 4 opened at the top end by centrifugal force.

Separation plate 5 separates 1! The remaining fine powder I'i is guided to a fine powder conduit 6 that short-circuits both discharge ports, and is separated and recovered as a material F from a fine powder discharge lower that is opened on the axis.

Figure 1 A: In the case of a two-port conduit, does the way it spreads out in the direction of travel form a straight line at a certain angle?
It may have a plurality of angle changes, such as three-stage bends, or it may have a curved surface. In short, it is necessary to satisfy the requirement that the centrifugal force increases at the end of the conduit as it progresses.

In practice, as a separating plate, knife etching as shown in the figure is preferable, and it is more preferable to use known means to induce the fine powder by applying negative pressure to the outside of the fine powder discharge lower to avoid generating a suction effect. Needless to say, it is functional.

The port in Figure 1 shows another embodiment, in which a centrifugal force is applied to the material S to be classified, which is supplied from the supply port 2 at one end to the conduit 3 which rotates at high speed around the axis C and widens toward the end, to coarsely move the material S to the outer circumferential side. Either the fine powder F is separated from the powder G toward the inner circumference, or the coarsest coarse powder G is discharged from the first discharge port 4, and as it continues, it is subjected to a strong centrifugal force, and at the final end, it becomes powder M of intermediate particle size. is discharged from the discharge port 8, and only the remaining fine powder F is collected from the fine powder discharge lower on the axis through the fine powder flow path 6.

3, 4, and 5 show that the object of the present invention is solved by a different configuration, and the ultrafine classifier 101 in FIG. The material S to be classified that has entered 103 is classified into coarse powder G and fine powder F by centrifugal force and advances, and at the apex of the spread, the course is layered by at least one (two in the figure) separation plates 105A and 105B. Separately, the coarse powder G is discharged and collected from the discharge port 104 closest to the supply port 102, and the fine powder F is discharged and collected from the discharge port 0107 furthest from the supply port 2. In the illustrated example, the flow path is partitioned into three parts, and an outlet 108 is provided to separate and collect the powder \1 of intermediate particle size between the coarse powder G and the fine powder F.

The ultrafine powder classifier 201 in FIG. 4 has a configuration similar to that of the second example, but differs in that the conduit 203 widens at the end and is formed in a spherical shape.

As we have seen above, the separation plates 5, 105 and 205 may all be knife-shaped or preferably protruded at an angle that provides the most effective separation depending on the shape of the conduit and the shape of the opening at its end. desired.

The ultrafine powder classifier shown in FIG. 5 has a configuration similar to that shown in FIG. 1, except that a fine powder discharge port is provided at the end of a conduit 307 that widens at the end.

1. Effects of the invention] Based on the above-mentioned functions, the ultrafine powder classifier according to the present invention has a relatively simple structure and is easy to manufacture, operate, and maintain. It is possible to classify and collect only fine powder with a uniform particle size at all times.

(The classification effect continues to be strengthened as it progresses through the pipe, and the effect of separating and discharging only coarse powder in areas where large centrifugal force is exerted is unique.)

[Brief explanation of the drawing]

FIG. 1A is a vertical sectional view showing a different embodiment of the present invention, FIG. . Section 4 and FIG. 5 are vertical sectional views showing different embodiments, and FIGS. 6 to 8 are vertical sectional views showing different conventional techniques. 1... Ultrafine powder classifier 2... Supply port 3... Piping 4... Coarse powder outlet 5... Separation plate 6...
Pipe line 7 for fine powder...Discharge port 8 for fine powder...Discharge port C for intermediate particle size powder...
Rotation axis F...Fine powder G...Coarse powder~
1...Powder with intermediate particle size S...Material to be classified 21 (A) (B) (C) Figure Figure

Claims (3)

[Claims] (1) A supply port for the material to be classified is opened on the axis of rotation, and spreads out at an angle symmetrically from the axis, and the cross section is annular or evenly distributed on the same circumference symmetrical to the axis. A plurality of conduits having the same cross section are arranged in a rotatable manner, and an annular or identical pipe with a separating plate protruding toward the upstream side of the conduit at the end of the divergent end or in addition thereto, or in the middle thereof, is provided. An ultrafine powder classifier characterized in that a tubular coarse powder discharge port attached to each cross-sectional pipe is opened, and a fine powder pipe that short-circuits both discharge ports opens the fine powder discharge port on the axis. (2) A supply port for the material to be classified is opened on the rotation axis, and spreads out at an angle symmetrically from the axis, and the cross section is annular or evenly distributed on the same circumference symmetrical to the axis. A plurality of pipes having the same cross section are rotatably arranged, and coarse powder and fine powder are discharged at each end of the pipe separated by at least one set of separating plates protruding toward the upstream side of the pipe. An ultrafine powder classifier characterized by having each outlet opened. (3) A supply port for the material to be classified is opened on the axis of rotation, and is spread out at an angle symmetrically from the axis, and the cross section is arranged in a circular pipe or evenly distributed on the same circumference symmetrical to the axis. A plurality of pipes having the same cross-sectional shape are rotatably provided, and one or more coarse powder discharge ports are opened in the middle of expansion with a separating plate protruding toward the upstream side of the pipes, An ultrafine powder classifier characterized in that a fine powder discharge port is opened at the end of the widening end, and each discharge port has a ring shape or a tube shape each attached to the same cross-sectional shape.